Introduction: How to Make a Portable Handy Lie Detector in Altoid Tin

Picture of How to Make a Portable Handy Lie Detector in Altoid Tin

Hi. I'm paewookyung, and this is my first posting in this site. please take note that
english is not my mother tongue. so please understand some of my gramatic mistake.;

Anyway, let's get this started!
This is a portable lie-detector built in Altiod tin. maybe you could have some fun useing this thing.

note: this detector is less sensitive then a real one. this could be miss some (many) of the lies.

Step 1: Things You'll Need.

Picture of Things You'll Need.

You will need some things below for this project.

1. circuit board
2. 10K& resister
3. 47K& resister
4. 470& resister
5. 1M& resister x2
6. 47K& VR
7. knob for VR
8. 2N3904 transistor x3
9. 0.1 ? mylar cap
10. slide switch.
11. 9V bettery snap
12. LED (one red, one green)
13. solding tools.
14. drill
15. basic tools,
16. valcro
17. aluminum foil
....and most of all, Altoid tin!

Step 2: Make a Finger Pads

Picture of Make a Finger Pads

make a finger pads by sticking a aluminum foil to the valcro.
And don' forget to stick a wire between the valcro and thw foil!

Step 3: Solding the Circuit

Picture of Solding the Circuit

Solder the circuit as a diagram below. And before solding the circuit, cut the circuit board to

suitable size to fit in the Altoid tin

Step 4: Drilling the Altoid Tin

Picture of Drilling the Altoid Tin

Drill the Altoid tin for a VR.

and DO NOT use a sharp-end drill bit. it will tear the tin into half.

Step 5: Put the Floor Sheet

Picture of Put the Floor Sheet

Put the floor sheet in a floor of the tin to avoid circuit from 'shorting'.

and secure is with a glue.

in my case, I used a piece of box, and secure with a hotmelt.

Step 6: Put Everything in Order.

Picture of Put Everything in Order.

Put everything in a Altoid tin and secure all of them with a glue, hotmelt, E.T.C

Step 7: Done.

Picture of Done.

Now your lie detector is ready to go. first, put the finger pad to the finger of the 'suspect'
then, slowly, turn the VR until the 'true' LED is light, and the 'false' LED is dark.
then, ask a question to the suspect , when the false LED get light, the suspect is lying.

Step 8: Enjoy!

Picture of Enjoy!

Just Enjoy that detector. but take this in your mind, this may not be detect lie so perfectly.

And sorry about mistake the 'welcome' to 'walcome' is the photos.

So...have fun.....


FarabeeK (author)2017-11-28

can anyone please tell me how it will sense lies with skin it would require a sensor and code to tell if the person is twlling the truth or lying

Sefane (author)2017-01-17

when i made this the red led did not light up why?

alabamajoe64 (author)2017-01-09

if i move my hand or body it will sometimes go red. if i touch them both together then it will go to red then back to green if i let go. so I am I close to getting it to work. Like I said could not get all the parts, I do have two of the green leds that are at 2 volts. may have to try this. and I think the project is so in a week or so, Help

alabamajoe64 (author)2017-01-09

I used a 100k VR and one of my led (green) is 3v and the red is 12 volts.I could not get the right stuff, is this why it is not working

Sefane (author)2016-12-03

what does vr stand for in this project in send him an email but he did not respond and i want to make this for my science fair

Prakhar. (author)Sefane2016-12-06

Variable Resistance

Sefane (author)2016-12-03

Where did you by the 47k variable resistor with numbered knob

Dylan3D made it! (author)2016-08-14

made it on a breadboard, worked great. Use a 50v 330uF capacitor

ahaana kashyap (author)Dylan3D2016-10-13

can i use 2n2222 or 2n4401 or bc547 instead of 2n3904?

vishnu 1962001 (author)2016-06-19

How can it detect lie

Dylan3D (author)vishnu 19620012016-08-11

resistance in the skin

vishnu 1962001 (author)2016-06-19

Did anyone try to make it ? I think its very simple . Its a topic for my science project too. Can anyone tell me how it works.(the science behind it) anyways.... it is amazing to have a selfmade "Lie Detector"

shelby kinsey (author)2016-03-19

It was a lot fun building this, but there are 1 or 2 things that you will need that are not listed.

What is this?

Could you mention those things?....please

shelby kinsey (author)2016-03-19

I had problems getting the red light to work, also.

Beast in the East (author)2016-03-12

I want to try that:-)

grimreaper122 (author)2016-02-02

how does this work

Atia Hussain (author)2015-12-31

i really have 1 week more to submitt my seesional project.that is so important for me. i need a complete guidance of your project so kindly help me . bcuz no doubt your project is superab.

scranckjack (author)2015-12-21

please whoever made this, this has just been giving to me as my project topic, please i need you contact. I am just pleading

WolfMaster333 (author)2015-12-09

Where am I supposed to get this stuff?!

CarloC15 (author)WolfMaster3332015-12-09

rapid electronics is a nice place

WolfMaster333 (author)CarloC152015-12-10

Thanks CarloC15

watermelonpicker (author)2015-11-18

What wattage is needed for the 47K potentiometer? And what is this red light problem that people keep commenting about?

KiaraP2 (author)2015-11-16

how does this work please?? send to plz

LindaT21 (author)2015-09-11

hey can you please send me a step by step guide on how to assemble the lie detector? My email is
Great project !!

Ayush0007 (author)2015-09-04

Please bro you have a video

HannaS5 (author)2015-08-29

So cool! I so want to do this... thank you!

dschoeman (author)2015-07-10

Anyone actually get this to work properly? Just getting the red light problem :/ any ideas?

venkateshh1 (author)2015-07-10

can you send me the back view of the finished circuit board?my email is

sairak (author)2015-04-09

kindly tell me how can we make this project based on microcontroller???

epicTCK (author)sairak2015-06-09

That would be a waste of 20 bucks. Arduinos are cool, but alot of projects use arduinos when they are not needed. Unless you have to have one to make the project work, they tend to be a waste of money, and space.

tyscof (author)epicTCK2015-06-11

Pretty easy to find "Arduinos" for around 3 bucks

epicTCK (author)tyscof2015-06-11

where? in that case useful, but 21 dollars seems a bit much to me when you could usually make the project without.

noraiz.tahir (author)2015-05-07

you need to show two capacitors in the circuit diagram where we should attach the second capacitor and plzzz tell me what will be the value of that capacitor

sairak (author)2015-04-09

how can we make this project baised on microcontroller

sandhyaar (author)2015-03-16

HI.. this project looks quite simple.. But.. whats the assurance that it detects lie?? Can u please explain that perspective??

bwclark101 (author)2015-03-11

I am sorry I mean, do you need the VR?

bwclark101 (author)2015-03-11

Do you need to VR?

seemab.ali.5439 (author)2015-02-26

it's too much easy ... because i make it

nom_zy (author)seemab.ali.54392015-03-06

hi bro...can u send me snap of ur project coz m crently working on this project???

KassidyGarvey (author)2015-01-20

I saw this back in October and wanted to do it for a school project so I went to radioshack and ace to try to find everything and ended up going to radioshack multiple times to get the parts. I built this with my dads help because i am new to circuits and we haven't been able to get it to work. the LEDs won't light up, we connected the LEDs to a wire and then to a 9 volt and they light up but then when we connected the 9 volt into the circuit nothing happened. can you maybe tell me what might have gone wrong? you can email me and i can send you pictures of what it looks like thank you!

BilalS2 (author)KassidyGarvey2015-02-01

did you connected leds to 9volts with or without the limiting resistor?, if without then your leds are probably toasted.

yhdesai (author)2015-02-01


sowmya.ganti (author)2015-01-17

where do we attach that knob in the circuit..??

the circuit is not so clear..!!

manolis.kasos (author)2014-12-25

Can sb explain the working of the electronics of this and if anybody has tested this and if it works

suyesh.gupta.33 (author)2014-12-21

can we use subsitute for Altoid tin

Fission Chips (author)2014-10-21

Awesome project! Thanks for putting this on the site.

did this work for you

bhawan.kumar.140 (author)2014-11-19

plzz post the block diagram

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